1) Field of the Invention
The present invention relates to an optical module in which an optoelectronic component is mounted on a waveguide substrate, and a method for production of such an optical module. In particular, the present invention relates to a method for production of an optical module according to which an optoelectronic component can be precisely aligned with an optical waveguide on a waveguide substrate, and an optical module in which an optoelectronic component can be precisely aligned with an optical waveguide on a waveguide substrate.
2) Description of the Related Art
In recent years, development of optical communication systems which can transmit and receive signals of large capacities has been proceeding. In particular, in the optical modules for realizing switching, optical multiplexing and demultiplexing, photoelectric conversion, or the like of optical signals, increase in manufacturing efficiency is required as well as improvement in optoelectronic components and waveguides contained in the optical modules.
The optical modules are produced, for example, by forming an optical waveguide made of quartz or a resin-based material on a substrate made of Si or the like, and mounting an optoelectronic component such as an optical deflection element on a surface on which the optical waveguide is formed. In order to minimize optical loss in light which propagates between the optical waveguide on the substrate and the optoelectronic component in such optical modules, it is necessary to precisely align the optical axes of the optical waveguide on the substrate and the optoelectronic component with each other. In particular, in the case of the single-mode optical waveguide, which is generally used in optical communication systems, highly precise alignment of optical axes with precision of submicron order is required.
Generally, when an optical waveguide is formed on a quartz substrate, it is difficult to precisely control the core height above a surface of the substrate. Therefore, it is necessary to achieve precise alignment when an optoelectronic component is mounted. In order to address this problem, a mounting method which can control the height of an optoelectronic component above a substrate has been proposed (see, for example, Japanese Unexamined Patent Publication No. 2001-330762). According to the proposed mounting method, a great number of globular quartz spacers are deposited on a mounting surface of a substrate on which an optoelectronic component is to be mounted, and the optoelectronic component is placed on the globular quartz spacers, and fixed with an adhesive. In this case, it is possible to adjust the height of the optoelectronic component mounted on the substrate, according to the diameter of the globular spacers.